There are multiple problems in crypto_unregister_instance:
1) The cra_refcnt BUG_ON check is racy and can cause crashes.
2) The cra_refcnt check shouldn't exist at all.
3) There is no reference on tmpl to protect the tmpl->free call.
This patch rewrites the function using crypto_remove_spawn which
now morphs into crypto_remove_instance.
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
diff --git a/crypto/algapi.c b/crypto/algapi.c
index 83b04e0..0f1976e 100644
--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -99,10 +99,9 @@ static struct list_head *crypto_more_spawns(struct crypto_alg *alg,
return &n->list == stack ? top : &n->inst->alg.cra_users;
}
-static void crypto_remove_spawn(struct crypto_spawn *spawn,
- struct list_head *list)
+static void crypto_remove_instance(struct crypto_instance *inst,
+ struct list_head *list)
{
- struct crypto_instance *inst = spawn->inst;
struct crypto_template *tmpl = inst->tmpl;
if (crypto_is_dead(&inst->alg))
@@ -167,7 +166,7 @@ void crypto_remove_spawns(struct crypto_alg *alg, struct list_head *list,
if (spawn->alg)
list_move(&spawn->list, &spawn->alg->cra_users);
else
- crypto_remove_spawn(spawn, list);
+ crypto_remove_instance(spawn->inst, list);
}
}
EXPORT_SYMBOL_GPL(crypto_remove_spawns);
@@ -554,28 +553,20 @@ EXPORT_SYMBOL_GPL(crypto_register_instance);
int crypto_unregister_instance(struct crypto_alg *alg)
{
- int err;
struct crypto_instance *inst = (void *)alg;
- struct crypto_template *tmpl = inst->tmpl;
- LIST_HEAD(users);
+ LIST_HEAD(list);
if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
return -EINVAL;
- BUG_ON(atomic_read(&alg->cra_refcnt) != 1);
-
down_write(&crypto_alg_sem);
- hlist_del_init(&inst->list);
- err = crypto_remove_alg(alg, &users);
+ crypto_remove_spawns(alg, &list, NULL);
+ crypto_remove_instance(inst, &list);
up_write(&crypto_alg_sem);
- if (err)
- return err;
-
- tmpl->free(inst);
- crypto_remove_final(&users);
+ crypto_remove_final(&list);
return 0;
}
--
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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